is there any difference is brewing with a resistored or non-resistored element?

No, not really.

"Resistored" elements refer to the anode/coupling being resistored, not the heating element itself. By using a resistor to limit galvanic current the anode life can be extended. Pretty much a moot point for our application, although it may help a little with the face of the element rusting? (probably only if you use their resistored anode as well though) It is a Rheem thing, so you usually only see it offered by them.

Rheem's heating element does have a resistor mounted on the rear of the element to prevent premature failure of the the element by slowing down corrotion. Above link in my old post shows the resistored anode and heating element.